1. Field of the Invention
The present invention relates to a disposable nozzle adapter for intranasal spray containers and, more particularly, to a disposable spray nozzle adapter for intranasally spraying a viscous medical solution in combination with a spray container.
2. Description of the Prior Art
In the treatment of rhinitis, medical sprayers or spray containers have widely been used to administer medical solutions to nasal cavities. Since medical substances are absorbed easily through nasal mucous membranes, the intranasal administration of medical substances has attracted much interest recently for the purpose of systemic treatment.
The sprayers or spray containers of the prior art generally comprise a pressurized container or a container with a manually-operated pump, and a spray nozzle fixed to the container. If such a spray container is applied for intranasal administration, especially for collective administration of medical substances such as, for example, influenza HA vaccine, it is required to use the same spray container for a number of people as the container is filled with a medical solution several times the required quantity for a dose. This makes a unfavorable impression on the person to be intranasally administered and causes a danger of infection of diseases if any one of the group has an infectious diseases such as acquired immune deficiency syndrome (AIDS).
An easy solution for these problems is to wipe or disinfect the nozzle of the container with a disinfectant each time. However, such an operation is troublesome and leaves the problem of a unfavorable impression unsolved.
It may be a good solution to use a removable spray nozzle in combination with a spray container, as disclosed for example, in lying-open Japanese patent No. 60-85759 (corresponding to U.S. Pat. No. 4,801,093). This spray nozzle comprises a top-closed cylindrical external member with a central channel, and a substantially cylindrical internal member arranged in the central channel of the external member to form a passage, said external member having a spray opening formed in the top wall of the external member and communicated with the central channel through one or more grooves carved on the inner surface of the top wall and through a cavity surrounding the spray opening.
In use, the spray nozzle is fitted on a valve stem of the spray container with a manually operated pump to complete the spray unit, and a medical solution in the container is sprayed through the spray opening by operating the pump.
This spray unit provides an excellent spraying action for a medical solution with a relatively low viscosity, but it is impossible to spray viscous medical solutions in finely divided particles. For example, if the spray unit is used for intranasal administration of medical solutions having a viscosity of 500 to 3000 cps, the solution is never sprayed in finely divided particles, but is ejected linearly like a jet because of its high viscosity. Thus, if the solution is ejected when the person breathes in, the solution would be sucked into the trachea and, worst of all, into the lungs.